Various types of automotive alternators are known. It has been found particularly advantageous to use interdigeted pole or claw-pole type alternators with the armature windings on the stator, and a rotating field. The a-c output of the alternators is rectified, preferably in diode-type bridge rectifiers, of which one rectifier is provided to supply the load, and another rectifier assembly may be used, separately, to supply field current. Reference is made to U.S. Pat. No. 3,320,498 which shows a rectifier assembly secured to individual heat sink plates which are positioned in crossed relation to each other and spaced from each other by spacing elements. U.S. Pat. No. 3,739,210 shows a rectifier assembly for connection to generators which are shaped in partial ring form and which have conductive plates which form cooling or heat dissipating plates secured on an insulating plate.
A stacked, interlaced or sandwich-type rectifier assembly is described in German Patent DE-PS No. 22 50 557 in which the heat dissipating or heat sink plate is an essentially circular element having finger-like projections. The fingers of the respective cooling elements interdigit in such a manner that the finger of one cooling element fits in the gap between two fingers of another cooling element. U.S. Pat. No. 4,059,778-Sohnle, to which German Disclosure Document DE-OS No. 26 03 786 corresponds discloses a crossed arrangement of cooling or heat dissipating sheet metal elements which are flat and are suitable for association with or assembly with three-phase alternators. It is customary construction to insert rectifier diodes into one of the end bells or end covers of an alternator.
The various known constructions have to be built to fit specific arrangements, and they can meet only very specific requirements. If the rectifier diodes are inserted into an end bell of an alternator, the alternator can be adequately cooled and the rectifiers can be well cooled; it is difficult, however, to test the alternator, the rectifier diodes and, in case of defects, to replace the end bell and the diodes, since they have to be disconnected and new ones reconnected. Repair thus is a problem; further, the construction is specific to particular alternators and thus stocking of parts for different kinds of alternators, both for manufacture as well as for repair purposes causes problems. If the support for the rectifier diodes is a flat plate, the diodes themselves are frequently not sufficiently cooled. Forming a cooling assembly with crossed dissipating or heat sink plates and fingers requires substantial space which frequently is not available in the alternator-rectifier combination, which should be as compact as possible. Constructing the cooling plates as segmental elements, similar to a quarter-moon, has been found to provide inadequate cooling and the construction is subject to fissures and breaks. It is difficult to insulate such structures within an alternator to prevent the formation of sneak or stray currents.
Some arrangements use two cooling plates or cooling or heat dissipating elements; thus, only one group of diodes is secured to the end bell of the alternator, the other to the additional heat dissipating plate. Such additional plates have been usually assembled to the end bell as additional, separate elements which require separate assembly steps both in manufacture, and disassembly and re-assembly upon repair. Since automotive alternator structures are subject to extremes of vibration and shock, the respective elements have to be reliably secured together which requires care and hence expense in manufacture as well as upon repair or maintenance.